In hard disc drives in personal computers, and the like, motor sound in driving, wind sound of rotating disc, or the like generates, becoming noise to operators or device-neiboring persons. Therefore, it is attempted to reduce the generated sound by arranging a soundproof material between the drive body and the substrate.
Hitherto, foams comprising a polyurethane foam and the like have been known as the above-described soundproof material, but there is a problem that the leakage of sound is large and they are poor in the sound insulating effect. Thus, a soundproof material wherein a static spring constant of the foam is limited, a soundproof material wherein a finely uneven polymer film is formed on the surfaces of the inside walls of bubbles of the foam, a soundproof material wherein the outer surface of the foam thereof is covered with a film, a soundproof material wherein a melt blow layer of a resin and the like is laminated on a film, etc., are proposed as disclosed in JP-A-56-157347, JP-A-59-102294, JP-4-40381, JP-A-4-345834, and JP-A-7-261768 (the term "JP-A" as used herein means an "unexamined published Japanese patent application".
However, in these conventional soundproof materials, the sound insulating effect is insufficient, a satisfactory sound proof of noises cannot be achieved, and in the soundproof material having formed a fine-uneven polymer film, etc., there is a problem that the production step is complicated and the production efficiency is poor.